The Food and Drug Administration is set to take its first step Friday toward regulating cannabidiol, or CBD.

The CBD product craze — with its myriad oils, capsules, gummies, lotions and potions — has exploded into a frenzy never before seen in the supplement industry.

On Friday, the FDA will hold its first public hearing on cannabis and cannabis-derived compounds, the most popular of which is CBD.

The goal of the hearing is to gather information on a wide range of topics related to products containing these compounds. Dozens of interested parties are scheduled to speak, including doctors, consumers and members of the cannabis industry.

"This is definitely setting a new precedent," said Andrew Shao, interim senior vice president of scientific and regulatory affairs at the Council for Responsible Nutrition, a trade association for dietary supplements.

"It's an important first step, and a number of stakeholders, including members of Congress, are looking to this meeting to inform the pathway forward on CBD," Shao told NBC News.

The FDA's principal deputy commissioner, Dr. Amy Abernethy, recently sent out a string of CBD-related tweets, writing in part: "We are reviewing available databases and medical literature about CBD’s safety. Thus far, the data appear insufficient."

"What happens if you eat food with CBD in it, use CBD-infused skin cream, and use other CBD-based products on the same day? What if you use these products daily for a week or a month, or longer?" she tweeted.

Outstanding questions and unproven claims

By itself, CBD does not cause users to become "high." (Marijuana's high comes from a different compound, THC, or tetrahydrocannabinol.)

Of course, people have been ingesting or inhaling CBD in the form of recreational marijuana for many years. What's different now is that CBD has been isolated as an ingredient and incorporated into supplements and various products.

That's led a number of experts to question the compound's safety.

"In terms of safety, we really don't know," said Dr. Pieter Cohen, who studies drug ingredients in the marketplace at the Harvard Medical School and the Cambridge Health Alliance. "We don't have a mechanism in the United States to effectively regulate [supplements] and ensure those products are safe."

Those products — and there are many — are marketed as ways to treat a slew of health problems, including insomnia, anxiety and chronic pain. Some CBD products even tout their ability to make the hair shiny and the skin glow.

The majority of those claims remain unproven. There have been a few small studies on CBD, but none of the large and robust clinical trials needed to prove that a medication is A, safe, and B, effective, leaving most of CBD's alleged abilities purely theoretical, according to experts.

And that can have harmful consequences.

"People may be avoiding truly effective treatments because of their belief that CBD will benefit them," said Dr. Peter Lurie, president of the Center for Science in the Public Interest, a consumer watchdog group.

Lurie said CBD was a topic of discussion when he was with the FDA in the early 2000s. "That was always one of our concerns, that [the products] promise the earth and there’s just really no science to back them up, except for some very isolated claims."

One use of CBD for which there is strong science to back it up is Epidiolex, which is the first and only FDA-approved cannabidiol medicine. The drug, which was approved last year, treats two rare and severe forms of epilepsy that affect children. (The FDA previously approved a few marijuana-based drugs, such as Marinol and Syndros, used to treat severe appetite loss and nausea in diseases like AIDS.)

But the approval of Epidiolex threatens the use of CBD in other, unapproved products. That's because current law states that if an ingredient is first developed as a drug — like Epidiolex — it cannot be sold in foods and supplements. This is why the FDA has repeatedly said CBD products sold over the counter are illegal. The agency has also sent warning letters in the past to companies selling CBD products that claimed to prevent or treat serious diseases like cancer.

Industry groups want action

Supplement industry groups are urging the FDA to take action on CBD. "We’re concerned there are a number of companies just taking advantage of the wave, really not knowing what they're doing," Shao, of the Center for Responsible Nutrition, said.

The financial implications are enormous. According to a study from cannabis researchers BDS Analytics and Arcview Market Research, CBD sales in the U.S. are expected to exceed $20 billion by 2024.

The market really took off in 2018, when Congress passed the Farm Bill, removing hemp from the controlled substance list. But even though hemp was legalized, products derived from it, like CBD, were left to the FDA to regulate.

None of this, however, has stopped the influx of new CBD products. "You have a situation where there are a lot of products in the marketplace, but they’re not necessarily legal," Shao said. The companies "may not be following existing regulations around labeling, around good manufacturing practices, and that can potentially place consumers at risk."

"At least with Epidiolex, you have a strong reason to believe that what the company says is in the product really is. But who's to know what is in some gummy bear?" Lurie said. "For all you know, there's no CBD, or for that matter, there could be too much," he added. Indeed, a 2017 study in the journal JAMA found that many CBD products contain higher or lower amounts of the compound than what's listed on the label.

The intent of Friday's hearing is to gather information only; no decisions will be made. It could take years for any kind of CBD regulation to be put in place, frustrating industry insiders.

"Our members are sitting on the sideline because they want to be in compliance," Shao said. "They are waiting for a framework so they can legitimately and legally develop high-quality products with CBD."